Grinding device and grinding method wherein a grinding unit can operate on-board as well as off-board

Abstract

A grinding device and a grinding method for grinding at least one knife. The grinding device includes a frame with a knife holder and a grinding unit comprising a grinding head, a grinding head holder, and a grinding head drive assembly. The grinding unit can selectively be connected with the frame or can be disconnected from the frame and can be placed on a cutting assembly with knives to be ground. In both operating modes the grinding head drive assembly rotates the grinding head and moves the rotating grinding head with respect to the grinding head holder.

The invention claimed is: 
     
       1. A grinding device comprising:
 a stand-alone frame comprising a knife holder arranged to hold at least two knives to be ground, one after the other; and 
 a portable grinding unit, comprising:
 a grinding head; 
 a grinding head holder holding the grinding head; and 
 a grinding head drive assembly configured to rotate the grinding head with respect to the grinding head holder, and move the grinding head along a curved trajectory in contact with the one knife, and subsequently the other knife of at least two knives to be ground, thereby grinding a cutting edge of the one knife and subsequently the other knifes held by the knife holder, and 
 
 wherein the stand-alone frame further comprises a releasable connection to the portable grinding unit, 
 wherein the grinding head drive assembly is further configured to move and to rotate the grinding head when the portable grinding unit is connected with the frame, and when the portable grinding unit is disconnected from the frame and mounted to a cutting assembly of an agricultural harvester to grind at least two knives of the cutting assembly, one after the other. 
 
     
     
       2. The grinding device according to  claim 1 , wherein the knife holder is configured to hold the one knife and subsequently the other knife to be ground in a position in which the cutting edge of the knife to be ground extends in a vertical plane. 
     
     
       3. The grinding device according to  claim 1 , wherein the grinding head comprises a shaft extending along a shaft axis and the knife holder comprises at least one pair of parallel plates extending perpendicular to the shaft axis, and the at least one pair of parallel plates is arranged to inhibit movement of the one knife and subsequently the other knife to be ground in a direction parallel to the shaft axis. 
     
     
       4. The grinding device according to  claim 1 , wherein the frame is arranged to be moved over ground. 
     
     
       5. The grinding device according to  claim 4 , wherein the knife holder is mounted on a chassis comprising at least one ground-engaging wheel. 
     
     
       6. The grinding device according to  claim 1 , wherein the portable grinding unit is positioned vertically above the frame when connected with the frame. 
     
     
       7. The grinding device according to  claim 1 , wherein the grinding head comprises:
 a shaft; and 
 a sequence of grinding bodies mounted on the shaft; 
 wherein the grinding head drive assembly is arranged to rotate and to move the shaft and thereby the grinding bodies with respect to the grinding head holder, and 
 wherein the grinding bodies are arranged for one of the grinding bodies to contact the one knife, and subsequently the other knife of the at least two knives to be ground. 
 
     
     
       8. The grinding device according to  claim 1 ,
 wherein the grinding head holder rests on a foot of the portable grinding unit, and 
 wherein the distance between the grinding head holder and the foot is changeable. 
 
     
     
       9. A grinding device comprising:
 a stand-alone frame comprising a knife holder arranged to hold at least two knives to be ground, one after the other; and 
 a portable grinding unit comprising:
 a grinding head; 
 a grinding head holder holding the grinding head; and 
 a grinding head drive assembly configured to rotate the grinding head with respect to the grinding head holder, and move the grinding head along a curved trajectory in contact with the one knife, and subsequently the other knife of the at least two knives to be ground, thereby grinding a cutting edge of the one knife and subsequently the other knife held by the knife holder; wherein the stand-alone frame further comprises a releasable connection to the portable grinding unit, 
 
 wherein the grinding head drive assembly is further configured to move and to rotate the grinding head when the portable grinding unit is connected with the frame, and when the portable grinding unit is disconnected from the frame and mounted to a cutting assembly of an agricultural harvester to grind at least two knives of the cutting assembly, one after the other; 
 wherein the knife holder comprises:
 at least two parallel plates; and 
 a plurality of pins, 
 wherein each plate of the at least two parallel plates has a hole pattern with a plurality of holes, 
 wherein each pin of the plurality of pins is arranged to be shifted through a pair of opposing holes in each plate of the at least two parallel plates, and 
 wherein adjacent plates are arranged to carry a knife by means of at least two pins shifted through the opposing holes. 
 
 
     
     
       10. A grinding device comprising:
 a stand-alone frame comprising a knife holder arranged to hold at least two knives to be ground, one after the other; and 
 a portable grinding unit comprising:
 a grinding head; 
 a grinding head holder holding the grinding head; and 
 a grinding head drive assembly configured to rotate the grinding head with respect to the grinding head holder, and move the grinding head along a curved trajectory in contact with the one knife, and subsequently the other knife of the at least two knives to be ground, thereby grinding a cutting edge of the one knife and subsequently the other knife held by the knife holder; wherein the stand-alone frame further comprises a releasable connection to the portable grinding unit, 
 
 wherein the grinding head drive assembly is further configured to move and to rotate the grinding head when the portable grinding unit is connected with the frame, and when the portable grinding unit is disconnected from the frame and mounted to a cutting assembly of an agricultural harvester to grind at least two knives of the cutting assembly, one after the other; 
 wherein the grinding head comprises;
 a shaft; and 
 at least one grinding body mounted on the shaft; and 
 the portable grinding unit comprises a guiding assembly, 
 
 wherein the grinding head drive assembly is arranged to rotate and to shift the shaft and thereby the grinding body mounted on the shaft, and 
 wherein the guiding assembly is arranged to guide the rotated and shifted shaft of the grinding head with respect to the grinding head holder along a given trajectory. 
 
     
     
       11. The grinding device according to  claim 10 ,
 wherein the guiding assembly provides at least one shaft guiding surface, 
 wherein the rotated and shifted shaft stays in contact with the at least one shaft guiding surface, and 
 wherein the at least one shaft guiding surface guides the shaft with respect to the grinding head holder along the given trajectory.